Storage tank breather vent valve
Storage tank breather vent valve
(OP)
Hi, we're desigining a 5000 gal SS atmospheric storage tank for non-flammable liquid. Well be filling it at about 100 gpm and draining it at about 30 gpm. I simply need a breather vent to let the air out when filling, and let the air in when draining (its a little smelly so we'll be venting it to the roof).
My supplier has specified a $500 53-lb Crispin dual vacuum and pressure air release valve that looks awufully complicated to me for the required duty. Does someone have experience with a simpler breather vent valve?
Thanks!
My supplier has specified a $500 53-lb Crispin dual vacuum and pressure air release valve that looks awufully complicated to me for the required duty. Does someone have experience with a simpler breather vent valve?
Thanks!
Fran McConville





RE: Storage tank breather vent valve
http://www.protectoseal.com/18540chart.html
but the $500 price tag does not sound very expensive for something you are referring to as complicated.
also, the 30 gpm sounds like too small a number for withdrawal from a tank that size. make sure you are looking at all scenarios and not just the normal withdrawal rate. often overlooked scenarios for an atmospheric tank are draining after the flushing/washing or leak testing.
A 2" or 3" nozzle wide open when full will pass much more than 30 gpm. Also, if you have two tanks in parallel and you want to balance between the two tanks via a pump suction line, you can move a lot of liquid very fast!
most of these types of mistakes are caused by failing to look at how we commission and operate equipment at other than the design steady state..
RE: Storage tank breather vent valve
On a tank that small, check the maximum pressure it can handle. That may help reduce the vent size if you do use a P/V vent.
Tyco/Varec, Shand&Jurs, Groth are some other names to look up for P/V vents.
RE: Storage tank breather vent valve
RE: Storage tank breather vent valve
Is this the Crispin valve you are referring to?
http://www.crispinvalve.com/dualair.htm
Unless it is a "bullet" style storage tank that is being supplied, I would have some reservation for using this valve on a tank built to API-650 or API-620.
Determine the code to which you tank is constructed and follow the typical relief guidelines accordingly.
RE: Storage tank breather vent valve
I DO have a lot of experience with Groth and Protectoseal conservation vents and they are as reliable as gravity. The moving disc that opens and closes is called a Pallet. Base cracking pressure is about 1/2 ounce/sq in. Adding weight discs to the pallets raises the set pressure. The sealing member is a thin TFE sheet, that flexes to shed ice and contaminants.
RE: Storage tank breather vent valve
Fran McConville
RE: Storage tank breather vent valve